This invention relates generally to a horizontal multi-joint robot that is employed for conveying a wafer in a semi-conductor producing factory, and especially relates to an art for placing rotational driving sources concentratively in one place, thereby avoiding routing energy supplying means to the rotational driving sources, such as electric wires for power supply, and arrangements of oil hydraulic or pneumatic pipes, and to an art for reducing weights of moving parts.
Concerning a conventional horizontal multi-joint robot known as a scholar type, as shown in FIG. 5, a robot 100 has a construction wherein connecting parts 101 and 102 corresponding to joints of arms 103 and 104 with multi degrees of freedom, are equipped with arm rotational driving sources 105 and 106 that respectively drive the arms 103 and 104, and the arm 104 is equipped in its distal end with a robot hand rotational driving source 107 in addition to driving sources 105 and 106.
However, in the above-mentioned construction, it is needed to supply energy to the connecting parts between arms 103 and 104, and to distal end of the arm 104, for activating the arm rotational driving sources 105 and 106, and robot hand rotational driving source 107. For example, if each of the driving sources is a motor, it is necessary to connect an electric wire to each of the driving sources and if each of the driving sources is an oil hydraulic or air pressure motor, it is necessary to place the pipe arrangements for supplying pressed oil or air. Rotational movements of the arms and robot hand gives mechanical load to these electric wires and pipe arrangements, thereby reducing its own reliability. Further, placing the rotational driving sources in each of the arms increases weights of the moving parts, thereby increasing inertial moments of the moving parts, and decreasing transportable weights thereof.
This invention is made to solve the above-mentioned problems. One object of the present invention is to provide a horizontal multi-joint robot wherein rotational driving sources for arms and a robot hand are placed concentratively in a base member in order to eliminate the need for routing energy-supplying electric wires and pipe arrangements, thereby preventing rotational movements of the arms and robot hand from decreasing the reliability, and wherein inertial moments can be reduced by decreasing weights of moving parts.
In order to achieve the above-mentioned object, according to one aspect of the present invention, there is provided a horizontal multi-joint industrial robot in which plural arms are sequentially pivotally attached, a proximal end portion of the lowest arm is rotatably supported by a base, and a robot hand is rotatably supported by a distal end portion of the highest arm: wherein a rotational driving source for driving said arms and robot hand to rotate is contained in said base; and wherein a driving force transmitting mechanism for transmitting rotational driving force from said rotational driving source to each of the arms and robot hand is provided in each of the arms and connecting parts of the arms.
In the above-described composition, not limited to an electric motor, an oil hydraulic motor or a pneumatic motor can be employed as said rotational driving source. Besides, one driving source for arm rotation can drive at least two arms to rotate. Further, it is possible to locate the arm rotational driving source and robot hand rotational driving source separately.
Further, in the above described-composition, the rotational driving source which is contained in the base member rotates plural arms and a robot hand through the driving force transmitting mechanism which is provided in each of the arms and connecting parts. This composition eliminates the need for routing energy-supplying electric wires and pipe arrangements, and prevents a break or a damage of the wire caused by an increase of mechanical load due to the rotation of the arms and robot hand. Further, this composition makes it possible to reduce weights of the arms, which decreases inertial moments, thereby allowing transportable weights to be increased, and motion speed of the robot to become faster.
In the above-mentioned horizontal multi-joint industrial robot, said driving force transmitting mechanism includes a rotational mechanism for rotating said robot hand around the connecting part of the distal end portion of the highest arm.
Further, in the above-mentioned horizontal multi-joint industrial robot, said driving force transmitting mechanism includes a mechanism for supporting said robot hand so as to move in a seesaw manner in the distal end portion of the highest arm, and giving tilting motions to said robot hand. This composition allows the robot hand to move in an up-and-down direction, thereby enhancing workability.
Further, in the above-mentioned horizontal multi-joint industrial robot, said driving force transmitting mechanism includes a mechanism for supporting said robot hand so as to rotationally move around a horizontal axis in the distal end portion of the highest arm, and giving rotational movements around the horizontal axis to said robot hand. This composition allows the robot hand to rotate around the horizontal axis, thereby enhancing workability.
Furthermore, in the above-mentioned horizontal multi-joint industrial robot, said arms are sequentially attached from the base in order of first, second and third arms; wherein said rotational driving source comprises: an arm rotation motor for rotating said first and third arms; an arm extension motor for rotating said second arm; and a robot hand rotation motor for rotating said robot hand; and wherein said driving force transmitting mechanism includes a mechanism that said arm rotation motor drives first and third arms to rotate, and said arm extension motor drives said second arm to rotate. This composition allows one driving source for arm rotation to drive at least two arms to rotate, thereby making it possible to decrease the number of rotational driving sources.
Furthermore, in the horizontal multi-joint industrial robot, wherein said driving force transmitting mechanism comprises axes passing through each of the connecting parts of said arms, pulleys that are fixed on said axes, and belts that are looped between pulleys of proximal end portions and distal end portions of the arms. The composition that the pulleys and belts are employed in the driving force transmitting mechanism, suppresses noise and dust raising under operating conditions. Therefore, this is suitable for use in a semi-conductor factory.